Speech controlled phonetic typewriter

ABSTRACT

To convert speech directly into print as it is being spoken, by machine, is a goal that has been thwarted by two critical wants: (1) a way to perform many complex selective operations with great speed, and (2) a way to close the gap between continuous speech as an unbroken sequence of sounds on the one hand, and the distinctly separated words and spelling conventions of the printed language, on the other. Recently, taking advantage of the electronic computer&#39;&#39;s speed with multiplex programmed operations, acousticians have sought to achieve more accurate detection and separation of speech sounds. Such efforts have required programming and availability of extensive computer facilities to approach one step in the problem. The approach described here, however, detects and analyzes speech sounds instantaneously without a computer, converting the sounds by means of comparators, timers, filters, and switching circuits, into a real-time electrical phonemic analog of what is said; then it adds a special-purpose digital computer component to process and match syllabic sequences of sounds in the language. Thus, the computer element is smaller and is used not for phonetic detection but simply to give an output as close as possible to conventional printing as can be obtained by means of a prestored vocabulary of 12,000 words. The readout can be printed by a modern high-speed electric typewriter.

United States Patent Feb. 29, 1972 DavidThurston G iggs a/k/a D.Thurston Griggs [54] SPEECH CONTROLLED PHONETIC TYPEWRITER I Inventor -PT22R51?! fines e is e. 21 E5 1!!! Griggs, 5128 Rolling Road, Baltimore,Md. 21227 [22] Filed: Jan. 9, 1970 [21] Appl.No.: 1,739

[52] U.S.Cl. ..179/1 SA [51] 1nt.Cl. ..G10l 1/16 [58] Field ofSearch..l79/1 SA, 1 VS; 178/31;

[56] References Cited UNITED STATES PATENTS 3,225,141 12/1965 Dersch..179/1 SA 3,204,030 8/1965 Olson ..l78/31 3,428,748 2/1969Flanagan..... ....l79/l SA 3,234,332 2/1966 Belar ....179/l SA 3,265,8148/1966 Maeda.. ..179/31 3,383,466 5/1968 Hillix ..179/1 SA OTHERPUBLICATIONS Dolansky, On Certain lrregularities of Voiced-SpeechWaveforms, IEEE Transactions, Vol. Au-1 6, 3/68, p. 51- 56 INPUT T0UNVOICED FRICATIVE mmsoucm(ne5) i 10 DIPTHONG TRANSDUCER (no.8)

ADJUSTMENT Primary ExaminerKathleen H. Claffy Assistant Examiner.lonBradford Leaheey Attorney-Keith Misegades and George R. Douglas, Jr.

[57] ABSTRACT To convert speech directly into print as it is beingspoken, by machine, is a goal that has been thwarted by two criticalwants: (I) a way to perform many complex selective operations with greatspeed, and (2) a way to close the gap between continuous speech as anunbroken sequence of sounds on the one hand, and the distinctlyseparated words and spelling conventions of the printed language, on theother. Recently, taking advantage of the electronic computers speed withmultiplex programmed operations, acousticians have sought to achievemore accurate detection and separation of speech sounds. Such effortshave required programming and availability of extensive'computerfacilities to approach one step in the problem.

1 switching circuits, into a real-time electrical phonemic analog ofwhat is said; then it adds a special-purpose digital computer componentto process and match syllabic sequences of sounds in the language. Thus,the computer element is smaller and is used not for phonetic detectionbut simply to give an output as close as possible to conventionalprinting as can be obtained by means of a prestored vocabulary of 12,000words. The readout can be printed by a modern high-speed electrictypewriter.

H 1 6 CIairns, 12 Drawingfigures PAIENIEDFEIIZQ I912 3. 646,576

SHEET 1 [IF 9 20 26 m 482 L 2 ORAL I6 8 2 In L TRANSDUCER 4o 2TRANSCRIBER s9 84 TYPO- IL THROA SIGNALS MODULE SIGNALS GRAPHIC o 3 *TUNIT 5% CONTACT l4 (FIesz-a) (H09) 5 I0 I FIG.I wRITTEN OUTPUT I69INPUI' SIGNALS I STOPS I I UNVOICED STOPS I 88 I I DI FROM I FILTER IFILTER 2 FILTER 3 SILENCE DETECTOR STOPS OR 94+ l800-22OO 3800-46003400-3800 I I I I FILTER I FILTER 2 FILTER 3 1100- I700 I700 -20002000-2400 I82 I A I92 I FI+F2 I I I I I 80 T I I I I I86 I I I I I l I II I I (I90 I; 9 I70 UNDIFFERENITATED I L -L I f 9J E EM I INVENTOR F 4ADAVID THURSTON GRIGGS ATTORNEYS PATENTEUFEBZS I972 SHEET 8 0F 9 t 58'RD.TA ITORTAL *-I SIGNAL STRENGTH j 5 318 1 PEAK TOTAL ORAL 342 1 ORALPEAK INPUT 3e AMPL'TUDE COMPARATOR/J FROM SEQUENTIAL PEAK FIRST GATECENTERED 1 FILTERS Saw S 'Q I I 240- 960 QU TIE I CPS. DISCRIM" i 1CYCLES INATOR I EACH L g E 3 |2 1E I I -w I I 4, FIRST FORMANT I 5 qBANDWIDTH I I I 9 332 I I 330 358 i PX s S mG I 5 SW I I E 720 94OCPS346 5 DlPHTl-DNG ASSING 5 3 jg T"" l I 940-20065 354 g 5; 9 1! I i z 0 O2 U I T 35 2 u: 360 37 u i u w 4 37 T0 I (n 9, E A mmmse I T 3 r 1 310 I380 i g ,fi l i i 356 339M! /3 4O I I INPUT TRMBDUCER To TRANSCRTBERPRESENT MODULE 1 1 VOWEL DETECTION I UNIT I l v 3 l FIG 7 INVENTORATTORNEYS SPEECH CONTROLLED PHONETIC TYPEWRITER SPECIFICATION Thepresent invention relates to a mechanism which transcribes human speechof the standard American variety from any adult speaker, instantaneouslyand automatically into a typed printout that normally consists, 90percent or more, of words that are spaced and appear in conventionalspelling. The system comprises three modules and employs dual inputs, asshown in FIG. 1.

One of the objects and advantages of the present invention is that thereis provided a device that transcribes automatically to give a printedoutput which is over 90 percent in conventional spelling withseparations into words or syllabic units, instantaneously derived fromthe spoken input of standard American English.

A further object of the present invention is to provide realtimedetection and analysis of speech sounds achieved by preswitching soundsaccording to their six manners of production into separate analyticalcircuits for each type, namely, vowels, nasals, unvoiced fricatives,voiced fricatives, voiced stops and unvoiced stops.

A further object of the present invention is to better differentiate onefrom another the voiced stops (plosives) and nasals where two differentkinds of vocal inputs are used.

Another object of the present invention is to provide means forproducing distinctions between voiced stops and unvoiced and unreleasedstops (plosives) which are detected independent of voicing, whennecessary, by means of rate of change of signal strength and durationaltiming.

A further object of the invention is to provide specific detection ofspeech sounds regardless of differences of pitch as between differentspeakers. Detection of vowels based upon frequency measurements alone isobviated because the centrum frequency and peak amplitude for the firstformant are detected and measured and then correlated to centrum peakamplitude for the second formant, with a ratio characteristic for eachvowel sound, regardless of pitch.

Another object of the invention is to provide signal indications forundifi'erentiated stops, both voiced and unvoiced, for

an undifferentiated nasal and for an undifferentiated vowel, when thoseoccur, so that the most probable intended but slighted phonemes may beinterpolated in the processes of syllable and word formation by thedevice.

A still further object of the invention is to provide a means of singlevowel detection so as to reduce phoneme storage, the diphthongs beingidentified by a process based upon detection of the simple vowels, butsignaled out in the same manner.

Another object of the invention is to provide phonetic detectionprocesses which produce differentiation of 38 different phoneticentities which serve as phonemes for the transcription process, and twoadditional signals-(a) an indication of silence and (b) an indication ofsyllabic stress.

A further object of the invention is to provide separation betweensuccessive identical sounds where one terminates the first word and theother starts the next word, this being accomplished by timing theduration of each type of sound so that only one signal will pass duringthe normal duration of a single occurrence of the sound, but a secondsignal will be emitted when it is prolonged as a bridge betweensuccessive words as a repeated sound.

Another object of the invention is to provide, by taking the vowel asthe basis, for the analysis of the input by syllables, and the inventiondeals with up to 337 distinctive kinds of syllabic sequences ofdifferent types of phonemes. By means of these combinations, syllablesare separated in connected speech, and speech vocabulary is classified.Provision is made for reconstitution of erroneous syllabic formulations,also instantaneously. Certain nasals are accorded syllabic import where,through their position, they supplant an articulated vowel.

A further object of the invention is to provide for the accumulation ofseparated and identified syllables, which are combined according topatterns arranged in a prestored vocabulary so that words will beformed, the longest possible ones first, and to provide a printout inconventional prestored spellings as a result of this matching ofincoming material with what has been stored. This is both for ease ofreading and to separate words for printing from within the stream ofconnected speech.

Another object of the invention is to provide for a vocabulary of 12,000or more words and syllables in storage, with about 1,150 of these in asupplementary store so that short words of three or less phonemes printout independently but only after they have been useful as parts oflonger stored words.

A further object is to provide, by means of coded designations forstored syllables, variations of pronunciation permissible within thelanguage structure when these designations are matched to the storedvocabulary words for printout.

Another object is to provide for compensation for omissions in thestored vocabulary (mainly proper names) by printing a phonemic orsyllabic printout of incoming unstored verbal material in a closeapproximation to conventional spelling, with stress indicated;

Another object is to provide for a printout of punctuation and ofnumerals and also of letter designations for spelling from spoken inputsby means of the syllable designations and vocabulary matching processes.

A still further object of the invention is to provide for realtimeprintout designations at a speed of 10 phonemes per second for theentire vocabulary, except that printing of each word must delay untilcompletion of that word, the maximum time being approximately 2.5seconds.

Another object is to provide for 88 printout signals which are suitablefor a conventional high-speed typewriter or printer capable of handling10 characters per second. The 88 printout signals may also be adapted todrive a Braille printing device, as well as a conventional printer.

Another object is to provide for the 88 printout signals characterswhich provide capital letters for spelling or designation purposes,numerals, punctuation and indications of phonemes where stress hasoccurred as shown by vowels appearing in boldfaced type. A separatespacing indication signal to the printing module after words also isprovided by the invention.

The design of the invention permits a choice of vocabulary constituentsor substitution of various ones, either as an entire group or throughindividually altered circuits without requiring a wholly differentapparatus.

The invention provides at least two opportunities for recording spokenmaterial for subsequent delayed transcription-( l) a dual-trackrecording by oral and throat microphones jointly on tape, or (2) arecording of the output of the detected phonemes from the transducermodule on single track.

These and other objects and advantages of the invention will becomeapparent upon full consideration of the following detailed descriptionand accompanying drawings in which:

FIG. 1 is a block diagram of the three modules comprising the inventionaccording to the preferred and best mode of the invention and showingthat the transducer module employs two inputs;

FIG. 1A is a block diagram showing the manner in which FIGS. 1-9 areconnected;

FIG. 2 is a block diagram of the sound separator apparatus or unit ofthe transducer module;

FIG. 3 is a block diagram of the stops-or-silence detector;

FIGS. 4 through 8 show methods of detecting individual speech sounds andtheir components based upon the concept of filtering at variousfrequencies with necessary comparators, switches and attendingcircuitry, and in particular FIG. 4 shows a block diagram for detectingand processing stop speech sounds;

FIG. 4A shows a block diagram for processing undifferentiated voicedstop speech sounds;

FIG. 5 shows a block diagram for detecting and processing fricativesounds;

FIG. 6 shows a block diagram of a nasal unit for detecting andprocessing nasal sounds;

FIG. 7 shows a block diagram of a vowel detection unit for processingvowel sounds;

FIG. 7A shows a block and circuit diagram of a second formant scannerunit for processing the second formant of vowel sounds;

FIG. 8 shows a circuit and block diagram of a diphthong transducer unitfor detecting and processing diphthong sounds; and

FIG. 9 is a block diagram of the transcriber module 20 of FIG. 1according to the preferred and best mode of the invention.

Note also the following tables in the Appendix:

Table I is a chart in the specification of sequences of phonemes insyllabic formations;

Table 2 is a chart or listing of the regrouping of phoneme sequencesfrom NO-GO syllables into new syllables; and

Table 3 is a chart in the specification showing the proposed type fontconsisting of 88 figures or characters that are printouts of thetypographic unit of FIG. 1. Also included with the 88 figures is aspacing unit, totaling 89 signal inputs thereto.

Table 4' is a chart showing difi'erentiation of vowels according toformant peaks.

Referring now to the drawings, there is shown in FIG. 1 the transducermodule which accepts an oral signal which is received by a microphone(not shown) that picks up the voice that is spoken by an adult and isfed to the transducer module on oral signal line 12. Also provided tothe transducer module is a signal derived from a microphone positionedon ones throat above and to one side of one s Adams apple and insubstantial contact with the skin surface, and is fed to the transducermodule on conductor 14.

As is also shown in FIG. 1, the transducer module 10 sorts and detectsthe phonetic elements needed for subsequent transcription which isaccomplished in the circuitry and components of FIGS. 2-8 to bedescribed below, and produces 38 real-time electrical output signals onconductors 16 representing the phonemes that have been detected anddelineated, including diphthongs. Also within the conductors 16 are twoadditional outputs, one indicating duration of silence and oneindicating stress, to be described below.

The second or transcriber module of FIG. 1 is a modified digitalcomputer unit, more particularly described in connection with FIG. 9,and which receives the 38 phoneme output signals from conductors 16together with the two other signals indicating durations of silence andstress, respectively. The transcriber module divides its phoneme inputinto 337 types or patterns of syllables and makes words from a storedvocabulary of 12,000 or more words; and for syllables not stored, itarranges a similar printout. The output is appropriately coded so as todrive a high-speed typewriter or similar printing device 26, and thusproduces thereby its written output. The printing device 26, also calleda typographic unit, is responsive to activating signals of 88 differentcharacters including a punctuation signal, and provides stress forisolated syllables and provides spacing after each of the language unitsit determines.

Thus the third module is any suitable high-speed typewriter or similarprinting device which will accept the outputs of the transcriber module20 at speeds up to 10 characters per second with type font modified toaccord with the 88 outputs and space signals totaling 89 signals, asnecessary.

As is shown in FIG. 1A, there is shown the arrangement in which thevarious FIGS. 2-8 interconnect in forming the transducer module 10 ofFIG. I. In FIG. 2, there is shown the sound separator 30 having the oralsignal line 12 and the throat signal line 14 connected to sensorelements 32,34 respectively, which sensor devices amplify for analyzingthe inputs applied thereto for analysis as to kinds of speech sounds sothat they may be shunted through or conveyed to different subsequentanalytical circuits according to the kinds of speech and theirconstituent components, for detection of individual speech sounds inseveral determined categories. From the sensor device 32, an output isconveyed or coupled to a linear amplifier or, what is called herein, aVOGAD" 36, from whence it is fed to a set of switches or gates40,42,44,46,48,50; each of which passes the oral input when appropriatefor its category of kind of speech sound being analyzed. Thesecategories are six in number and relate in the following manner to theswitches 40-50.

Switch 40 unvoiced stops Switch 42 voiced stops Switch 44 unvoicedfricative Switch 46 voiced fricative Switch 48 nasals Switch 50 vowelsBy these divisions or separations of conventional electric analogs of anoral input, there are derived signals from switches 40-50 that providemeans of preswitching nasals, vowels and voiced fricatives.

Signal means of opening each of the gates or switches 40-50 likewise isshown in FIG. 2 by means of a series of three ratiometers 52,54,56,which act upon the ratios of amplitude of the signal strength in line 58from sensor 32 and from the signal strength in line 60, as applied tothe ratiometers 52-56. The signal strength in lines 58,60 essentiallyconduct or pass signals indicative of the strength of the oral andthroat inputs respectively, and an oral OFF-switch 62 coupled to line 58provides a ratio of change of strength signal to the ratiometer 54,while the sensor 34 provides an output to a 700-c.p.s. lowpass filter 64which provides an output to a throat signal differentiator 66 whichprovides a rate of change of signal strength to the ratiometer 56.

In the ratiometer 52, there is an amplitude comparison of signals ofabout 3 to 2 at the throat for indicating a vowel; a throat input signalratio of about 2 to 1 for providing the oral input indicating a nasalsound; a ratio of approximately I to l which characterizes a voicedfricative sound.

The ratiometer 52, when satisfied, activates a vowel gate over conductor52a in gate 50. The ratiometer 54, when satisfied, activates the nasalgate 48 over line 54a. The ratiometer 56 which provides an approximatelyl-to-l output comparison, when satisfied, provides activation of thegate or switch 46 which provides a voiced fricative indication.

During a rapid rate of change of oral input as shown by the sensors32,34, the ratiometers 52,54,56 are cut off so that transitional statesthat may be developed will not register inappropriate ratios therein. A700-Herz low-pass filter 64 is connected to the sensor 34 so that onlythe lower frequencies which are present and indicative of the signalsand information found in the throat input 14 are used for detection inthis process to develop rate of change output to the throatdifferentiator 66, and ON-OFF indications over conductors 70,72,respectively. The ON-OFF indications on conductors 70,72 are used asinputs to the stops-or-silence indicator 74 in FIG. 3. The ON output offilter 64 is provided as an input 76 to the voiced fricative switch 46,and the OFF-signal 72 is used as an input to the unvoiced fricativeswitch 44.

The stops-or-silence indicator 74, which more particularly is shown indetail in FIG. 3, has several inputs, namely, 70,72, as referred toabove, signal line 80 from throat difierentiator 66, signal conductor 82from the oral differentiator 62, and oral OFF signal on conductor 84,and oral ON signal on conductor 86, and an oral input from VOGAD 36 onconductor 88.

A threshold adjustment means is connected from the output of the sensor32 to a stress signal terminal 92.

There are seven general output signals from the stops-orsilenceindicator 74, three of which are applied to the unvoiced stops switch40, i.e., conductors 94,94,169, two of which are applied as outputsignals to the voiced stop switch 42 over conductors 96, 96, an outputto a silence terminal 98, and an output from a switch that showsprobable presence of a stop, which output passes by conductor 128 toclose the unvoiced fricatives gate 44 in FIG. 5. This prevents mistakenidentification of an unvoiced stop as an unvoiced fricative in theprocess shown in FIG. 5.

An output 169 used as an indication of an undifferentiated unvoicedstop, hereinafter defined as p, t, or k," is used also to pass throughthe unvoiced stop switch 40 and then into the detection circuit of FIG.4A.

Shown in FIG. 2 is the output of the linear amplifier or voltage VOGAD36 to which input is applied over conductor 12. The output of VOGAD 36provides a signal over conductor 88, as described above, to thestops-or-silence unit 74, and a further output to the unvoiced stop gate40 over conductor 110, an output also to the voiced stop gate 42 overconductor 112, an output to the unvoiced fricative switch 44 overconductor 114, an output to the voiced fricative switch or gate 46 overconductor 116, an output to nasal switch 48 over conductor 118, and anoutput to the vowel switch 50 over conductor 120. These outputs fromVOGAD 36 are used in conjunction with deriving the gated output of theswitches 40-50. The outputs of these switches 40-50 are applied tofurther circuit units of the system as shown in the output terminalextending below the switch in FIG. 2 so that the output of switch 40 isapplied as an input to FIG. 4; stop 42 is applied similarly to FIG. 4A;the switch 44 is applied to FIG. 5, respectively; switch 46 to FIG. 5,respectively; nasal switch 48 to FIG. 6, respectively; and vowel switch50 to FIGS. 7 and 7A, respectively. The signals from the VOGAD 36 areused to derive a measure of stress to be used in the transcriber moduleof FIG. 9 through the above-described arrangements. In the stressindication, an adjustment is provided as threshold adjustment 90 to thethreshold above in which there is to be an indication of stress. Theoutput 92 is applied to FIG. 9, as is shown and will be described indetail below.

Similar to the VOGAD unit 36 for the oral signal of conductor 12, thereis also a VOGAD unit 122 connected to conductor 14 which carries thethroat input signal, and the output of VOGAD 122 is applied as a gatesignal to the nasal switch 48 over conductor 124.

FIG. 3, which has been described in part above, shows thestops-or-silence detector 74 which receives inputs 70,80,82,84,72,86,88,and which emits six outputs as shown. The purpose is to distinguish thetrue silence from various kinds of stops or plosive sounds and todistinguish the different kinds from each other when possible. However,when not possible, a signal for undifierentiated unvoiced stops isproduced in conductor 94. The stops-or-silence detector is provided withvoiced stops switch 126, and the unvoiced stops switch 142. It alsoprovides a direct oral plosive input direct to the detection ortransducer circuits for the unvoiced stops over conductor 94, and forthe voiced stops over conductor 96. The two remaining outputs areindications of undifferentiated unvoiced stops over conductor 169, andof silence over conductor 98. The method of operation is essentially bymeans of timers and delay circuits, such as silence timer 130, a0.01-second timer 132, a timer 134, a 0.06-second timer 136, a thirdtimer of 0.04-second delay 140, and switches 141,142,144.

Prerequisite to all regular stops must occur a silence of at least 0.04second followed by a rapid rate of change of oral signal. Delay switch140 detects this from inputs 72,84,82, releasing signal 128 when theseconditions occur. For voiced stops, a comparator 146 uses inputs of theoral and throat rates by conductor inputs 82,80 to establish whetherthere is greater than 1:1 ratio; and if so, and if the throat voltmeteror VOGAD 122 is in its ON-condition 70 and there is a stop signal fromdelay switch 140 with 128, the voice stops gate 42 is activated. Thesilence output over conductor 98 depends on four inputs, that is, theoral VOGAD or voltmeter OFF condition from conductor 84, the throatvoltmeter OFF condition from conductor 72, the absence of oral voltmeterON condition from conductor 86, and the absence of indication of oralrate of change from oral differentiator circuit 62 from conductor 82. Ifthe throat and oral input are OFF for 0.04 seconds, as determined bydelay 140, and if there is no rate-of-change signal, a switch 141 emitsa signal which may eventuate in a silence output over conductor 98; butwith a rate of signal change present, the switch 142 will emit a signalto open the unvoiced stop gate over conductor 94. This separate switch142 will open the gate only when there is determined to be a throatvoltmeter OFF indication received over conductor 72. To return to theincipient silence signal from switch 141, a silence indication will passto produce an output on conductor 94 showing silence if timer is thussatisfied for 0.15 seconds; but if an oral voltage cuts in sooner fromconductor 86, no silence indication is passed via conductor 98.

It is seen that thus far there are distinctions made between differentkinds of stops, as well as between the stops and silence breaks in thespeech which are assumed to be detectable upon a clear and intelligiblespeech input to the system. However, there are stops which are notsufficiently clear to be distinguished by the foregoing method ofanalysis; for these a separate provision is made to feed the input tothe stops transducers in FIGS. 4 and 4A, as follows. The oral input 88is suspended and stored by a timer of 0.01 seconds (timer 132) which istriggered by the switch 141 through conductor 128. The timer alsoreceives an oral rate of change input 82. When there is a continuingrate of change during that time, the oral input undergoes additionalsuspension and storage up to 0.06 seconds as determined by an additionaltimer 136; and if during that succeeding 0.06-second interval, there isa rapid rate of change of oral input, then the stored plosive or stoporal input is supplied to the unvoiced stops transducers over conductor94. It is supplied from the retaining timers 132,136 of of the stops orsilence detector rather than through the normal opening of the gate. Ifthere is no variation in the rate of change during the 0.01 second oftimer 132, the oral input signal instead of passing to the 0.06 secondtimer 136 is switched to 0.03 second timer 144 for retention. Then it isreleased to the transducers either of voiced 96 or unvoiced 94 stops,depending upon the reading of the associated comparator 144. Thiscomparator has two settings as to fast or slow rate of change during the0.03-second period, switching the stored input to unvoiced stops 94 toFIG. 4 with rapid change, or to voiced stops 96 to FIG. 4A with slowrate of change.

The foregoing described programs or processes will not handle theunvoiced stops which are not released and not distinct enough to beanalyzed from ordinary speech in the transducer circuits beyond thegates. In order to determine the presence of such undifferentiatedstops, i.e., p, t, or k, the oral voltage ON and OFF inputs and oralrate of change readings are used in the timer 134 which receive fromconductor 84 the oral OFF signal, from conductor 86 the oral ON signal,and from the oral differential signal from conductor 82. The timer 134is set for 0.15 seconds and is a maximum transducer, activated only whenthere has been a high rate of change followed by zero change with oralvoltage nil. If the oral voltage recurs within 0.15 seconds, theassociated transducer in timer 134 emits a signal over conductor 169 forundifferentiated unvoiced stops. However, if there is a silence longerthan 0.15 seconds, the transducer in timer 134 is not activated and thecircuit output provides nothing.

FIG. 4 shows detection of individual unvoiced stops by stops detector150. There are two inputs to the stops detector 150, namely, theunvoiced stops over conductor 88 processed by the stops or silencedetector of FIG. 3, and the direct input from the gate 40 in FIG. 2applied over conductor 94. The transduced undifferentiated unvoicedstops signal from the stops or silence detector of FIG. 3 is carriedover on conductor 169 as an additional output of unvoiced stops gate 40.For detection of /p/, filters 152,154 are used with the resultingvoltages compared in a comparator 156. Filter 152 passes l,8002,200c.p.s., and filter 154 passes signals in the band 3,8004,600approximately, while the comparator 156 provides an output of filter152, filter 154 being greater than one. This means that a ratio showingthe output of filter 152 to be greater than filter 154 output will givea transduced output signal for the sound /p/ on conductor 164. Fordetection of /k/, there are provided a filter 154 and filter 158, filter158 passing a band of frequencies between 3,400-3,800 c.p.s., so thatthe resulting outputs of filters 154,158 are applied to a comparator 160wherein the voltage amplitude of filters 154,158 is greater than unit 2,such that the ratio of filter 154 and filter 158 must be more than 2:1to give the transducer output for the sound /k/ on conductor 166. Fordetection of /t/, the voltages from filters 158, 152 are correspondinglycompared in comparator 162 wherein a ratio of output voltages of morethan 2:1 for the outputs of filters 158 and 152 provides determinationof the transducer signal for /t/ on conductor 168.

FIG. 4A illustrates how a similar process is arranged for detection ofthe individual voiced stop sounds in a circuit called voiced stoptransducer 170. Two inputs, namely, the oral input shown in FIG. 2, passthrough the voiced stops gate 42 and provided from conductor 42a,together with a separate signal from the delayed input from thestops-or-silence detector of FIG. 3 over conductor 96.

The inputs to the undifierentiated voiced stop 170 from conductors 42aand 96 are fed to an ON-OFF detector 172 used to show there is an activeinput from either source over conductors 42a and 96. The ON-OFF detectorfeeds an input to each of band-pass filters such as filter 174 passing1,lOl,700 c.p.s., filter 176 passing I,700-2,000 c.p.s., and filter 178passing 2,000-2,400 c.p.s. The ON-OFF detector also provides a signal togate or switch 180.

The output voltages passing filters 174,176,178 are applied to acomparator 182 so that the voltage from filter 174 is compared togetherwith the combined voltage output from filters 176,178. Comparator 182thus compares the output of filter 174 to the sum of outputs fromfilters 176,178, and if the order of magnitude of the comparison isgreater than unity, an output of comparator 182 on conductor 184 isderived indicating the sound /b/ on conductor 184. The output thus istransduced or present inly if the ratio is greater than 1:1.

The detection for /g/ by comparator 186 is developed by applying theoutput of filter 178 for comparison with the sums of outputs of filters174,176, so that when this comparison or ratio is less than unity, anoutput on conductor 190 provides the detection of /g/. FIG. 4A alsoproduces a signal for the sound /d/ which is detected when there is avoltage output derived from filter 176 over conductor 192 to a switch194. Switch 194 produces the output in conductor 196 when there is inputover conductor 192 from filter 176 simultaneously compared with theabsence of outputs from comparators 182,186 over conductors 184,190,respectively. Thus the sound /d/ is detected when there is the absenceof detection of sounds /b/ or /g/, respectively.

In order to determine the presence of an undifferentiated voiced sound/b/, /d/ or /g/, outputs from conductors 184,190,196 are applied to thegate or switch 180. The presence of an output from the ON-OFF detector172, but in the absence of any specific filter output over conductors184,190,196, switch 180 produces or releases a transducer signalindicating an undifferentiated voiced stop on conductor 200.

FIG. 5 shows a fricative transducer module 202 for detection of bothvoiced and unvoiced fricative sounds by means of a network stage of fivelow-pass filters 210,212,214,216,218 coupled by comparators220,222,224,226,228. Low-pass filter 210 passes up to 10 k.; filter 212passes up to 8 k.; filter 214 passes up to 5 k.; filter 216 passes up to2.5 k.; and filter 218 passes up to l k. Input signal on conductor 88from VOGAD 36 of FIG. 2 is applied to the low-pass filter 210 and tototal signal switch two-way 230 which processes about 96 percent of thetotal signal strength of applied unvoiced fricative signal on conductor44a from switch 44 (FIG. 2), or processes about 60 percent of the totalinput signal on conductor 88 for voiced fricative signal on conductor460 (FIG. 3). The voice input 88 is capable of interruption by switch206 activated by the stops-or-silence detector in FIG. 3 throughconductor 128. This input therefore will be lacking when a stop ispresent.

The two-way output of total signal switch 230 is applied to each of thecomparators 220,222,224,226,228. The two-way output is actually realizedby the conductor 46a for the voiced fricative signal being applied to avoltage-responsive switch means 234, which upon actuation thereof,mechanically activates a series single-pole-double-throw (SPDT) switches240,242,244,246 from an initial position (shown vertically) to anactuated position (shown diagonally disposed) by lever means 248,schematically illustrated in dotted lines.

Now having described the physical arrangements, it is shown in FIG. 5that the oral input signals present on conductor 88 are passed throughthe IO-k. low-pass filter 210 which output is applied to the comparator220 which compares the output of total switch 230, i.e., either 96percent of the total signal strength in case of unvoiced fricative, or60 percent of the total signal for a voiced fricative. If the comparisonof the l0-k. filter, output/total switch output is greater than 1:1,SPDT-switch 240 connected to the output of comparator 220 passes anoutput signal for lunvoiced th/, unless two-way switch 234 is activated;in such case, an output signal lvoiced th/ is produced, as shown.

The IO-k. low-pass filter 210 output is applied over conductor 250 tothe 8-k. low-pass filter 212, which output is applied to the comparator222 for comparing the output of total switch 230, as above described. Ifthe comparison of the 8-k. filter output/total switch output is greaterthan 1:1, SPDT switch 242 connected to the output of comparator 222passes an output signal /f/ unless two-way switch 234 has been actuated;in such case, an output signal /v/ is produced, as shown.

The 8-k. low-pass filter 212 output is applied over conductor 252 to the5-1:. low-pass filter 214, which output is applied in turn to thecomparator 224 for comparing the output of total switch 230, as abovedescribed. If the comparison of the S-k. filter output/total switchoutput is greater than l:l, SPDT-switch 244 connected to the output ofcomparator 224 passes an output signal ls/ unless two-way switch 234 hasbeen activated; in such instance, an output signal /z/ is passed, asshown.

The 5-k. low-pass filter 214 output is fed over conductor 254 to the2.5-k. low-pass filter 216 which output in turn is fed to the comparator226 for comparing the output of total switch 230, as above described. Ifthe comparison of the 2.5-k. filter output/total switch output isgreater than l:l, SPDT- switch 246 connected to the output of comparator226 passes an output signal /sh/ unless two-way switch 234 has beenactuated; in such instance, an output signal lzh/ is passed from theswitch 246.

The 2.5-k. low-pass filter 216 is fed over conductor 256 to the l-k.low-pass filter 218, which output in turn is fed to the comparator 228for comparison with the total switch 230 output, as has been described.If the comparison of the l-k. filter output/total switch output is lessthan 111, output conductor 250 passes a sound /h/. It is noted that theratio is less than that of 1:1 showing that the l-k. filter will havecritically cut the frequencies within its band range, therefore properlyidentifying the proper /h/ speech sound.

Switch 234 is a mechanical gang switch activated by the voicedfricatives gate 46 of FIG. 2, so as to switch the transducer output froman unvoiced fricative to the voiced fricative sound that is in the samebandwidth.

In general, therefore, the same process of comparison and switchingcontinues through the cascade of filters 210-218, except that with thelast one (I-k. filter 218) there is no further filter, and a ratio ofless than 1:1 when present will signal the presence of an /h/.

FIG. 5 there is seen to yield output signals indicative of /0/, lvoicedthl, /f/, /v/, /s/, /z/, lsh/ lzh/ and /h/, a total of nine speechsounds.

FIG. 6 illustrates the nasal detection 260 having oral input fromconductor 12 and throat signal input 14 (see FIG. 2). These signals arecoupled for reinforcement of the lower frequencies on conductor 262;FIG. 6 produces the detection of nasal sounds /m/, /n/, /ng/, andundifferentiated nasal or /n/, and /l/.

The conductor 262 having reinforced input signals thereon is applied inparallel to each of band-pass filters including filter 270 passing700-1,200 c.p.s. filter 272 passing 1,300-2,800; filter 274 passing700-1,000; filter 276 passing 1,400-2,l; filter 278 passing 2,000-3,000;and filter 280 passing 1,600-2,000.

The outputs of filters 270 and 272 are applied to ratio or amplitudecomparator 282 which produces a signal on conductor 284 indicative ofthe /m/ sound when filter 270 output/filter 272 output is greater thanunity.

The outputs of filters 270 and 272 are applied to ratio or amplitudecomparator 286 which produces a signal on conductor 288 indicative ofthe /n/ sound when filter 272 output/filter 270 output is greater thanunity.

The outputs of filters 274 and 276 are fed to a ratio or amplitudecomparator 290, which produces a signal on conductor 292 indicative ofthe lng/ sound when filter 274 output/filter 276 output is greater thanunity.

The outputs of filters 278 and 280 are fed to a ratio comparator 294which produces a signal on conductor 296 indicative of the /1/ soundwhen the filter 278 output/filter 280 output is greater than unity.

The filter 274 output is fed to a gate or switch 300 to which also isfed the output of comparator 282 on conductor 284, the output ofcomparator 286 on conductor 288 and the output of comparator 290 onconductor 292; such output of switch 300 is a signal, if any, indicativeof an undifferentiated nasal sound, i.e., [7] on conductor 302. Avoltage through filter 274 between 700 and 1,000 I-Iz. will yield anoutput unless outputs on conductors 284,288 or 292 show the presence ofa specifically identified /m/, /n/ or lngl.

The vowel detector 310 in FIG. 7 operates with only two inputs: the oralinput signal on conductor 50a in FIG. 2, and total oral signal strengthcomponent on conductor 58 in FIG. 2. In summary, it produces transducedoutput signals, conductors 311 representing 10 vowel sounds including/r/ and one undifferentiated vowel signal. Eight of the vowel signalsare supplied to the diphthong transducer of FIG. 8, and three of themare supplied directly to the transcriber module 20 of FIG. 9. Inaddition, a ratio signal for peak amplitude of first formant as afunction of total signal strength 344 is passed to the diphthongtransducer in FIG. 8.

The method used in differentiating vowel sounds is to compare the peak(centrum) amplitudes of the first and second formants relative to eachother and to the total oral amplitude at the same time, then to checkthis against the frequency of the first formant. Detection of the firstformant follows conventional methods by using a bank of filters 312 at20-Hz. intervals between 240 and 960 Hz. This enables determination ofthe frequency of the first formant centrum. Detection of the secondformant in FIG. 7A is done differently-through scanning for the peak,without regard for the exact frequency, by means of heterodyning.

The input signal from the vowel gate on conductor 50a of FIG. 2 isdiverted into two different circuits, one for each formant, and itsupplies a transducer 340 which indicates the presence of any kind ofvowel input whatever, described in detail below. The first formantdetector 312 receives the input voltage to a bank of 36 sequentialcentered filters of 20-cycles bandwidth in the range from 240 to 960 Hz.The 36 filtered outputs are supplied over individual conductors 314 to acomparator called a peak and centrum discriminator 316, which reads thepeak amplitudes values in output 318 and determines whether the centrumlies within certain particular bandwidth ranges: 400-700 Hz. passingover conductor 321; 340-460 I-Iz. passing over conductor 322; 260-400Hz. passing over conductor 323; 240-340 112. passing over conductor 324;400-700 Hz. passing over conductor 315; 400-500 I-Iz. passing overconductor 326; or 700-940 Hz. passing over conductor 327. Determinationof the location of the centrum in these bandwidths is used to helpdifferentiate the vowels when the peak amplitude ratios are compared.The method of differentiation is shown in the chart of Table 4 (seeAppendix), where amplitude ratios are derived from the Peterson-Barneystudies.

From the input signal for total oral signal strength on conductor 58, acomparator 342 also receives the first formants peak amplitude readingfrom conductor 318 and compares these, producing a ratio output onconductor 344 for the first formant quotient. This is supplied to afinal comparatorratiometer 346 associated with the transducer 348 forthe vowel output signals 311.

For the second formant process in scanner 328, the input signal ispassed through a pair of bandwidth filters, a filter 332 passing 720-940Hz. from oral input conductor 50a, and the other filter 350 passing940-2900 Hz. The voltage from filter 332 resulting at below 940 issubject to close-off by a switch 330 which is activated when the firstformants centrum shall have proved to be located in that bandwidth asapplied over conductor 327 because in that case the second peak willformant above 940 Hz. The filtered voltages from the paired filters332,350 are supplied over conductors 352,354 to the second formantscanner 328 which is shown in detail in FIG. 7A. It produces an outputof second formant peak amplitude on conductor 358 and an indication whenthe second formants centrum was above 1,050 B2. on conductor 356, bothto be described below. That indication on conductor 356 is supplied tothe vowel transducers 348 where it is needed for substantiativediscrimination between certain vowel phonemes as shown in Table l Acomparator-ratiometer 346 receives the second formants peak amplitudereading through connector 358 and also an input of the total signalstrength component on conductor 58. This ratio output from ratiometer346 is then supplied to a comparator 360 for comparing the ratios ofpeak amplitude of the first and second forrnants as quotients of thetotal signal strength. Preset ratios according to Table 1, when met,will activate the vowel transducers 348 in combination with the inputsof information concerning first formant bandwidth from conductors321,322,323,324,325,326,327 from the second formant scanner 328. Theresulting transduced output signals 311 for presence of the variousvowels to the diphthong transducer in FIG. 8 are on conductors 371-378,and to the transcriber module 30 of FIG. 9 over conductors 379,380, thelatter for sounds which do not appear in diphthongs.

Whenever a vowel is detected by the vowel transducers 348, a signal isemitted over conductor 339 and passed to the undifferentiated voweltransducer 340 so that it will not put out a signal on conductor 341 foran undifferentiated vowel. However, whenever there is a vowel inputthrough the vowel gate over conductor 50a without identification of aspecific vowel, the transducer 340 will supply its output direct to thetranscriber module 20 of FIG. 9 over conductor 341.

FIG. 7A is a detail of the second formant scanner 328 whose purpose isto detect and measure the peak amplitude of the second formantregardless of the frequency of its peak and to determine whether or notthat peak lies in the range of 1,050 to 2,900 Hz. The method used is toheterodyne the incoming signal so that peak-measuring voltmeters can beused to read the peak. Input voltages in the range from 720 to 2,900 Hz.passing over conductor 354 are merged on conductor 390 as they emanatefrom two filters passing 720-940 Hz. passing over conductor 332. Themerged voltages are fed through connector 390 to a mixer 392. The mixer392 is activated from a sweep oscillator 394 that linearly sweepsthrough the range from 10 kc. to 11.850 kc. The resulting signal onconductor 396 is passed through two filters of 20-1-12. bandwidth each,on filter 398 centered on 8,950 I-Iz., and the other filter 399 on 9280Hz. The filtered signal outputs of 398,399 then are separately suppliedto peak-measuring voltmeters 400,402. These voltmeters are activated insynchronization with the sweep oscillator 394 by means of an ON-OFFsignal applied over conductor 404.

In order to obtain the higher of the two peak amplitudes thus detectedin peak voltmeters 400,402 as an indication of the peak amplitude of thesecond formant, the respective signals are supplied to a third voltmeter406 the output of which supplies that information on conductor 358. Thatinformation from peak-voltmeter 406 is also supplied to a comparator409, also receiving output from voltmeter 400, comparator 408 measuringwhether the second formant peak was that peak which was detected by thefilter 399 centered at 8,950 Hz. through connector 358; so that if thepeak thus was in the range l,050-2,900 1-12., the comparator passes thatinformation as its output 356.

A diphthong transducer 420 of FIG. 1A and shown in detail in FIG. 8,processes single vowel outputs from the vowel detector 348 of FIG. 7 toidentify diphthongs when present, and it produces distinctive electricalsignals on conductors 42l,422,423,424,425,426 for six such diphthongs.Since it also relays the eight single-vowel signals 371-378 from thevowel detector 348, it passes all vowel and diphthong output signalsdetected by the transducer module 420 to the transcriber module 20.

The single-vowel signals 371-378 fed to the diphthong transducer 420represent the basic simple vowel phonemes of American English ascontinuous signals generally timed to last 0.2 seconds each except for/U/ and /u/ which are transmitted in single, somewhat shorter, pulses.The continuous signals allow retention of the single-vowel signalsduring the time required to determine whether or not they are used in adiphthong before releasing them. Since /U/ and /u/ occur onlyterminally, such delay is not required for them. Other inputs to thediphthong transducer 420 are a signal from the vowel detector 310 inFIG. 7, through conductor 344 from peak comparator 342 that gives theratio of the first formant signal strength to the total oral signalstrength. That input (344) is supplied to a memory unit 424 of 0.15seconds which is activated by the signal on conductor 426 from an ORcircuit responsive to a signal on any of 371-376 indicating the presenceof any vowel input except /U/ and /u/. The other input to the diphthongtransducer 420 is the rate of change of oral signal on conductor 82 fromFIG. 2. It is supplied each to the memory unit 424 and to a comparator430 of rates of change.

The presence or absence of a diphthong is determined in the transducer420 according to whether there is a steady rate of change of signalstrength when two vowels occur consecutively. The memory 424 of 0.15seconds determines the timing parameter for this comparison incomparator 430; and if there is only a steady rate of change, whichcharacterizes a diphthong glide, the comparator 430 activates a gangedswitch 434 which engages the diphthong circuits by means ofsinglepole-double-throw switches 441,442,443,444,445 ,446,447,448. Anunsteady rate of change from comparator 430 indicates that no glide ispresent and the vowels 311 are intended to be separate. Consequently,unless the comparator 430 is satisfied with a steady-state ratio, theswitches 441-448 are normally closed (upwardly, as seen in FIG. 8) in astate where the single, simple vowel signals will be transmittedfollowing the 0.l-second memory delay. Those output signals will pass tothe transcriber module through connectors451,452,453,454,455,456,457,458.

When the switch 434 is actuated (closed down, as seen in FIG. 8), thefollowing occurs. The leh/ sound signal in conductor 373 is applied totransducer 461 to combine with sounds /I/ or /i/ from switch 446, sothat a signal A" is produced in conductor 421. /I/ and /i/ merge inconductor 470.

The /I/ or /i/ sounds from switch 446 also combine in transducer 462with the signal /I)/ from conductor 376 passing switch 442, to produceloi/ in conductor 422.

The /a/ sounds from switch 443, or lg/ in conductor 464 from switch 444,combine in transducer 463 with the signal /I/ or /i/ in conductor 460 toproduce I in conductor 423.

The /8 sound from conductor 374 passing switch 444 merges with the /a/signal through connector 474 as a dialectal substitution for /a/. /a/ or/as/ is applied to transducer 464 with the outputfrom a rate detector475 to produce [au/ in conductor 424. The rate detector 475 isresponsive to the comparator 530 but detects that the ratio change ofthe comparator increases in a period of 0.2 seconds.

The /I/ or /i/ sound signal in conductor 470 combines in transducer 465with the merged /U/ or /u/ signals in conductor 476 to produce an outputfor U" in conductor 425.

The 12/ sound from switch 442 combines in transducer 466 with the outputfrom the rate detector 475 to produce /0/ on conductor 426.

The comparator 475 senses any increase within 0.2-second periods in theratio of the first formant peak amplitude to the total signal amplitudein the interval between the beginning and end of a diphthong. This isthe interval involved in the action of the memory unit 424. Thiscomparator receives the ratio signal through conductor 344 from thevowel detector of FIG. 7. Its timing is activated by an output from thecomparator 430. When there is an increase of the first formant strengthwithout a rapid rate of change of oral signal, the comparator 475 passesan output 477 to gates 464 and 466 to complete formation of diphthongs/ao/ and /0/ respectively.

The six diphthong output signals 421-426 supplement the eightsingle-vowel signals 451-458 in providing the complete vowel anddiphthong indications from the transducer module V 20 to the transcribermodule in FIG. 9.

The transcriber module 480 in FIG. 1, and shown in detail in FIG. 9,receives (in general) electrical signals representing the detectedsounds (39 in number) plus a signal representing the occurrence ofsilence and processes these, converting them to 89 output signals todrive the typing or printing mechanism 26 of FIG. 1. FIG. 9 shows thistranscriber module 480. It has six input channels-one for the silencesignal on conductor 98 from the stops-or-silence detector 74, FIG. 3;one for the stress indication via conductor 92 from the thresholdsetting 90 of FIG. 2; and four channels representing the categories ofspeech sounds, i.e., (l) switches 240-246 which come from transduceroutputs 220-228, 261 representing the fricative sounds both voiced andunvoiced in FIG. 5. Since none of these signals will occursimultaneously, they are merged in the fricative input channel; (2)stops from conductors 164,166,l68,190,196,200 which come from outputs oftransducers 156,160,162,169,l ,l86,194 representing the various stops,voiced and unvoiced and undifferentiated in FIGS. 4 and 4A, also merged;(3) vowels from conductors 371-380, 341, 421-426 which come from theoutputs of transducers 340,348 representing single vowels and diphthongsand undifferentiated vowels, in FIGS. 7 and 8, also merged; and (4)nasals from conductors 284,286,290,300 which come from the outputs oftransducers 282,286,290,300 representing the nasal sounds and /l/ andundifferentiated nasals in FIG. 6, likewise merged.

Input pulse dividers or time choppers 491,492,493,494 are placed in eachchannel and divide the pulse or signal input into a series ofapproximately equal periods, respectively, for each of the channels. Thetime chopper for fricatives and vowels are set to divide the appliedsignal into series of 0.2- second pulses, as long as the signal isapplied and, correspondingly, the time chopper for stops and nasals isset to divide the applied signal into series of 0.l-second pulses for aslong as the applied signal is present.

The transcriber module 480 is essentially a multiphase digital computerhaving a direct set program. It has two outputs: a spacing signal toindicate times between words on conductor 482, and a channel 484 for 88distinctive signals for printed characters.

The input signals are applied first to a phoneme sequence sensor anddesignator 490 to which the silence signal 98 also is applied since itspresence will signal grouping of inputs to constitute syllables. Thephoneme sequence sensor and designator 490 contains a storage of about337 syllabic combinations of fricatives from the four classes of soundsrepresented by its four channels. Basic to English, these syllabiccombinations are shown in Table 1 (see Appendix). When a possiblesyllable has been identified, its speech-element signals are passed asinputs over conduit 492 to the regrouper and storage means 494 of 5preselected actual syllables for that particular combination of classesof sounds among the 337 syllabic combinations. Consequently, sequenceindication on conduit 496 accompanies passing of the speech-elementsignals to facilitate the search in storage means 494. The storage ofactual syllables is combined with a unit for regrouping sequences ifthere is no match. The maximum capacity of this unit is 10 phonemes ornot more than 1 second, whichever is first. If, in a particular sequencethere is no match with a stored syllable, the sequence indication isaltered accordingly as the last phoneme of the nonviable sequence isdropped from it and the shorter sequence then tried. If it then fits,that last phoneme becomes the first one in a new sequence, then the lasttwo, then the last three, etc. This shortening and consequent regroupingof phonemes for the syllable involves identification of a differentsequence. Therefore, that information is passed back to the phonemesequence sensor and designator 490 through conductor 498 so that it canstart identification of a new sequence with the terminal elementsrejected from the previous sequence. Regrouping of phonemes startseither with that signal on conductor 498, with a silence input appliedon conductor 98, or upon receipt of a signal from conductor 482 fed todesignator 490 that shows completion of a syllable or word ready forprintout. The pat- :ierr; used for regrouping is shown in Tables 2(a b)(see Appen- If the actual syllable identified is not one that is used instored words of the vocabulary of 12,000 or so words chosen, or it itconsists of only two or three elements (i.e., appears to be a fragmentor remnant), it is passed through conductor 500 to a storage unit of twoand three phoneme units 501 where it is either matched with a storedshort word or is converted to printout signals in phonetic-phonemic formover conductor 532.

Upon identification of a syllabic sequence unit in designator 490 thatcould be part of a larger word in the vocabulary storage 516 ofmultisyllable words, the designation for that particular syllable issignaled to the storage unit 494 of vocabulary words through conductor492 and, simultaneously, the phoneme sequence units together are passedto a syllable retainer 510 through conductor 512. The syllable retainer510 has a storage capacity of up to nine syllables which it holds either(1) until their release as parts of a word that matches one in thevocabulary storage 516 through conductor 540, or (2) until the retainer510 is saturated, or (3) until there is a spacing input to indicatebeginning of a new verbal unit, as indicated on conductor 482. Theselatter two releases through conductors 500 and 520 pass to the storageof two and three phoneme units for short printouts. In the storage oftwo and three phoneme units 50], sequences that do not match about 1,600stored short words that will be printed conventionally over conduit 532will be printed in phonetic-phonemic manner, with stress shown byuppercase or bold printing in response to a stress signal on conductor92 coming from FIG. 2.

An additional input to the storage of two and three phoneme units 501 isprovision for supplying a period or dot whenever the silence inputreaches 1 second cumulatively. This is accomplished by a timer 522 ofone second operating on the silence signal 98 which will automaticallysignal what appear to be sentence endings or long pauses on line 524 tothe storage of two and three phoneme units 501. This same storage 501will convert inputs designating letters of the alphabet orally into thecorresponding capital letters for each.

The storage of word vocabulary 516 contains about 10,600 words that arearranged according to syllable designations within the 337 of thissystem, stored in the proper sequence. For each such stored word, thereis a corresponding coded printout signal which is activated through theoutput 530 to the printing unit 26, whenever there is an input ofsyllables that matches a stored word. In the case of punctuation, thecoding translates from the verbal name to the punctuational printoutdesignation. Upon release of a printout signal for any word, the storageof word vocabulary unit 516 emits a spacing signal through conductor 482which goes both to the syllable retainer 510 and to the phoneme sequencesensor and designator 490 as a signal for start of a new verbal unit.This spacing signal, of course, likewise goes to the typographic orprinting unit 26 at the end of each word. Since printout signals willnot emanate simultaneously from both the word vocabulary storage 516 andthe storage of two and three phoneme units 501, their outputs 530 and532 pass through the same connector 484 to the printing unit 26.

Table 3 (see Appendix) shows 88 printout characters and phonemicprintout symbols (with phonemic equivalents in parenthesis) for use inthe printing unit of FIG. 1. The 88 symbols are those which will beactivated by 88 distinctive signals through connector 484. The 89thsignal is for spacing which is applied over conductor 482.

Additional embodiments of the invention in this specification will occurto others and therefore it is intended that the true spirit of theinvention be limited only by the appended claims and not by theembodiment described hereinabove. Accordingly, reference should be madeto the following claims in determining the true spirit of the invention.

APPENDIX.'IABLE 1 [377 Phoneme sequence patterns in English-in fourcategories of phonemes] Code: V-vowel including/r/and/ll; terminaldiphthongs as single vowel units.

S-stop (plosive), voiced or unvoiced. F-fricative, voiced or unvoiced.

Nnasal.

V SVVV SVVVN FVVVS FSVN SFVN F FNVF VV FVVV SVVVNS FVVVSF FSVNS SFVNSSFFNVFS VVV NVVV SVVVNF FVVVSFS FSVNSF SFVNSFF FNVFF VVVV FSVVV FVVVSFFFSVNSS SFVNSFS FNVFFS SN SVVVNFS SVNF SFVNFS FNVFFF VVVN SVVVF NVNFSVNSSF SFVF FNVFSS SV VVVNS SVVVFS NVNS FSVNSFF SFVFS FNVFSF FV VVVNFSVVVFF NVNSF FSVNSFS SFVFF FNVS NV VV VNFS SVVVS NVNSS FSVNFS SFVFFSFNVSS FSV VVVF SVV VSF NVNF FSVF SFVFFF FNVSF SFV VVVFS SVVVSFS NVNSSFFSVFS SFVFSS FNVSFS FNV VVVFF SVVVSFF NVNSFF FSVFF SFVFSF FNVSFF FN VVVS ..NVNSFS FSVFFS SFVS FNVSSF V V VSF FVN NVNFS FSVFFF SFVSS FNVSFSF VNVVVSFS FVNS NVF FSVFSS SFVSF VNS VVVSFF FVNSF NVFS FSVFSF SFVSFS FNVVNVNSF FVNSS NVFF FSVS SFVSFF FNVVNS VNSS VVVVF FVNF NVFFS FSVSS SFVSSFFNVVNI" VNF VVVVS FVNSSF NVFFF FSVSF SFVSFSF VNSSF FVNSFF NVFSS FSVSFSVNSFS SVN FVNSFS NVFSF .SFVVN SVNF FVFF NVSFS SF\'\'F FNVVS FS VFFSVNSSF FVFFS NVSFF FSVVN SFVVFS FNVVSF F VFFb SVNFF FVFFF NVSSF FSVVNSSFVVFF VFFF BVNSFS FVFSS N'VSFSF FSV'VNF SFVVS FNVYY N VlBb SVNFfa FVFSF.FSVVN F SFYYSF 14 1\1\'\ N s VP'BY SVF FVS NVVN FSVYF SFVVSFS FN\'\'\'NF VS SVFS FVSS NVVNS FSVVFS SFVVS l" FNY N Fh VSS SVFF FVSF N'VVNFFSVYFF s FNY YF "SF SVFFS FVSFS NVVNFS VSFS SVFFF FVSFF NVVF VSFF SVFSSFVSSF NVVFS VSSF SVFSF FVSFS NVVFF VSFSF SVS FVVN NVVS SVSS FVVNS NVVSFSVV SVSF FVVNF NVVSFS FVV SVSFS FVVNFS NVVSFF NVV SVSFF FVVF FSV V VNFSSFVVVSF FSVV SVSSF FVVFS NVVVN FSVVVF SFVVVSFS SVSFSF FVVFF NV V VNSFSVVVFS SFVVVSFF VVN SVVN FVVS NVVVNF FSVVVFF VVNS SVVNS FVVSF NVVVNFSFSVVVS FNVN VVNF SVVNF FVVSFS VVVF FSVVVSF FNVNS VVNFS SVVNFS FVVSFFNVVVFS FSV V VSFS FNVNSF VVF SVVF FVV VN .FSV V VSFF FNVNSS VVFS SVVFSFVVVNS NVVVFF MFNVNF VVFF SVVFF F.V V VNF NV V V S SFVN FNVNSSF VVS SVVSFV V VNFS NVVVSF SFVNS FNVNSFF VVSF SVVSF FVV VF NV V VSFS SFVNSFFNVNSFS VVSFS SVVSFS FVVVFS NV VVSFF SFVNSS FNVNFS VVSFF SVVSFF FV V VFFAPPENDIX.-TABLE 2(a) I APPENDIX Table 3 [Sequences of phonemes insyllable formations] Key: fi i E or a a b c t l e i g h a ir l 'm n o pq r s t u v w x y z 2 3 v l I I I I I I I I 7 I I I I 7 I Y 1 I Y J I IY I I Nnas a l. (W 45.6.1.3, 9.4 ,1), .F, H. 1.1. K, L, M, 0.1. Q,V-vowal, r I 2 N b d a, 6, ii, 11, in k, 6 Bold face (only forphoneme-syllable um er 0O 8 (example only) print-out). E, I, 0 U, a, e,l, o, a, 6, o, u plus a spac ng an Initial sequences (may Phonemic moms.

stand complete): E g 1 s (I)-flnal part of St V i (1) r z dlphthongs:

47 6 5:) m 1 :11, A, I. g (3 n 11 U) final art I -ng s p 0 2g 35 o (0;,(6) p 211 (5) diphtho%s: 51 1 so, 0, 52 t tl1 53 1! MP 0 54 11 (u) b ch(1; 61 W- d 1' 40 y- (1-) 8 complete) 62 a h Terminal sequences: 1

-N 21 Norm-m. undlflerentiated nasal: m,n, or -ng; p. undifferentiatedp, 22 l; ork k- N Fr 24 ..J ba-'. 1 .h.1 d -v --N St St--. 23

t APPENDlX.-Tuble4 Distinguishing 29 peak ratios Frequency range 11Basis for confirmation $35-- Vowel 1st F 2nd F 1st F 2nd F andsupplemental distinction Fr St 16 -5 -15 440-540 xxx Fr 17 -1 -s(680-940) xxx (Peak amplitude ratios only). gi gt; 5 -1 -10 (580-800)XXX St 31 i g gg }Flrst formant ireq. range. "S g: 2 17 400-100 1,700-2, 400 First lormant freq. ra ge g 35 -3 --23 340-400 1, 800-2, 000(with second formant tre- F 37 4 -24 260-340 2,1s0-2,900 quency morethan 1,050). F r 33 260400 7504 050) First formant lreq. range t t r(with second formant ireq. St Fr St Fr 36 0 -7 520-640 (720-1, 030) lessthan 1 050) 1 Must be attached to one of the above.

' KFPENDIXETABLE 2 (b) [Re-grouping oi phoneme sequence]s from no-gosyllables into new syllables IMMEDIATE shift [or new terminal 5grouping: New initial sequence grouping: 1

28dc22t021- 28 becomes 44-46 or #48; 22 becomes 41-42 or #49. 236:24t022. 24 becomes 44-46 or #48; 23 becomes 41-42 or #49. 25 to 23-. 25becomes 44-46 or #48. Y 264227 to 24. 26 becomes 44-46 or #48; 27becomes 41-42 or #49. 29 to 28. 29 becomes 41-42 or #49. 138: 15 toll.15 becomes 44-46 or #48; 13 becomes 41-42 or #49. 1041 171:015. 11becomes 44-40 or #43; 10 becomes 41-42 or #49. 186: 14 to 13. 14 becomes44-46 or #48; 18 becomes 41-42 or #49. 326: 34 to31. 34 becomes 44-46 or#48; 32 becomes 41-42 or #49. 33 to 32... 33 becomes 44-46 or #48.356237 to34. 37 becomes 44-46 or #48; 35 becomes 41-42 or #49. 36 to 35-36 becomes 44-46 or #48. 46 to 48... 46 becomes 51.

4 e shewe ea elmeeeehswaJnTQle;(an.

In neg. db referred to 1st formant centrum for Wh le ance s;

l. Speech-to-writer apparatus comprising:

a detection and analysis transducer module receiving an oral and athroat signal input and having sound separation means for detecting,ditferentiating, processing and producing speech sound signals accordingto at least the following stated categories: (I) vowels and semivowels,(2) nasals, (3) unvoiced fricatives, (4) voiced fricativcs, (5)unvoiced-stops, and (6) voiced stops, said sound separation means (FIG.2) having sensors responsive to the oral signal and throat signalinputs,

a stops-or-silence means responsive to said sensors, ratiometer circuitsfed by said sensors and said stops-orsilence means to produce an outputsignal, and

a plurality of logic gate means selectively responsive to outputs fromsaid sensors, said stops-or-silence means, said ratiometer circuits, forsingularly passing processed speech.

2. The invention according to claim 1 wherein said sound signalsproduced by said transducer module are fed separately to a transcribermodule having a syllable storage and a wordvocabulary storage.

3. The invention according to claim 1 wherein a printout signal meansfor said transcriber module is connected to a typographic unit producinga written output of either conventionally spelled words or syllabicutterances.

4. The invention according to claim 1 wherein said sound separationmeans (FIG. 2) has:

an oral sensor gate receiving an input of said oral signal and producingdigital outputs indicative of oral ON and oral OFF,

a throat sensor gate and low-pass filter receiving an input of throatsignal and producing digital outputs indicative of throat ON and throatOFF signal,

differentiator means responsive to said oral sensor,

throat difi'erentiator responsive to said throat sensor,

said stops-or-silence unit receiving inputs of said oral signal, saidoral ON and said oral OFF signals, said throat ON and OFF signals, andsaid oral and throat differentiator outputs,

said ratiometer circuits receiving inputs from said oral and throatsensor gates, said oral and throat difi'erentiator outputs and producingratioed output signals, and

each said logic gate means receiving said oral signal, including anunvoiced stop gate receiving outputs from said stop-or-silence unit,

a voiced stop gate receiving outputs from said unvoiced stop gate andsaid stop-or-silence unit,

an unvoiced fricative gate receiving said oral ON signals and saidthroat OFF signal,

a voiced fricative gate receiving said throat ON signal and one of saidratioed output signals, and

a vowel gate receiving outputs from said oral gate and one of saidratioed output signals.

5. The invention according to claim 4 wherein (FIG. 4) said unvoicedstop gate provides an output to a stop unit comprised of a terminal forreceiving signals indicative of an unvoiced stop that isundifferentiable as to whether it is /p/, /t/ or /k/.

first, second and third band-pass filters for passing l,8002,200,3,800-4,600 and 3,400-3,800 cycles, respectively, and receiving theoutputs of said unvoiced stop gate and said stops-or-silence unitproducing filter output signals, and

a first, second and third comparator, said first comparator receivingoutput signals from said first and second filters, said secondcomparator receiving output signals from said second and third filters,and said third comparator receiving output signals from said first andthird filters.

6. The invention according to claim 1 wherein (FIG. 3) saidstops-or-silence means for voiced stops, unvoiced stops, and forsilence, comprises a comparator 146 receiving outputs from said oral andthroat differentiators and producing output when the amplitude of saidthroat differentiator output is equal to or greater than the amplitudeof said oral differentiator output,

a switch means 126 receiving said produced output, said throat ONsignal, and an output from a second circuit indicating the presence of astop, saidsecond circuit having a timer 140 receiving inputs of saidoral OFF and throat OFF signals and producing a delay gate output,

a switch 141 receiving inputs of said oral difierentiator and said delaygate output producing complementary outputs identified as silence signalwithout dt and stop with dt,

a timer gate (0.15 seconds max.) 134 receiving inputs of said oral ONand OFF and oral differentiator signals, to pass a predetermined delayedsignal representing undifferentiated unvoiced stops,

a silence timer gate receiving inputs of said silence signal without dtand said oral ON signal producing a silence signal,

an unvoiced stop gate 142 receiving inputs from said throat OFF signaland said stop with dt signal,

a timer (0.01) delay gate 132 receiving inputs of said oral signal fromsaid oral ditferentiator and from said second circuit means producingmutually exclusive outputs of greater or less than 0.0l-second delayduration,

a timer (0.06) 136 receiving inputs of said less than 0.01-

second delay duration and said oral signal, and also from the said oraldifferentiator, producing an output direct to the unvoiced stopstransducers,

a delay switch (0.03) 144 receiving inputs of said more than 0.0l-seconddelay duration, and said oral differentiator, and producing outputsdirect to both voiced and unvoiced stops transducers.

7. The invention of claim 1 wherein said detection and analysistransducer module comprises a nasal unit (FIG. 6) responsive to oral andthroat inputs, a plurality of filter comparators, one of saidcomparators deriving an /1/ signal and one deriving an undifferentiatednasal sound as a result of said added throat input.

8. The invention of claim 1 wherein said detection and analysistransducer module comprises a vowel detection unit FIG.

7) responsive to oral input to provide detection and dif ferentiation ofsingle vowels from each other by ratio comparison of first and secondformant peaks to total signal strength deriving vowel signals therefrom.

9. The invention of claim 8 wherein are means for deriving (FIG. 7A)second formant peak amplitude signals without reference to its frequencywhich is accomplished by heterodyning.

10. The invention of claim 9 wherein said transducer module operatessubstantially as well with oral input signals from either a male orfemale voice.

11. The invention of claim 8 wherein said vowel detection unit includesa transducer 340 receiving an oral input signal and a signal indicativeof the presence of an identified vowel, said transducer producing anoutput signal indicative of an undifferentiated vowel.

12. The invention of claim 11 wherein said transducer module comprises adiphthong transducer (FIG. 8) that distinguishes diphthong sound signalsfrom single vowel sound signals (371-376) by a differentiated oralsignal'applied to a memory, and a first formant quotient signal and froma signal from the ratio comparison of first fonnant peaks to totalsignal strengths (claim 9), said memory acting upon a comparator tocondition diphthong gates (461-466) to pass a diphthong signal, saidmemory also acting on a switch (434) to shunt nondiphthong sound signalsto a transcriber module.

13. The invention of claim 2 wherein said transcriber module (FIG. 9)comprises a phoneme sequence sensor and designator (490) for receivingsignals indicative of fricatives, stops, vowels, diphthongs, nasals, anda silence signal;

a regrouper and storage means 494 of preselected phoneme groupingsresponsive to the output of the designator,

a syllable retainer 510 having a storage capacity of syllables to beactuated by the regrouper means output, and

a word vocabulary 516 cumulatively responsive to the consecutive outputof the syllable retainer for producing print out signals of the longestword forms provided by spoken input.

14. The invention of claim 13 wherein said transcriber module inresponse to receiving said silence signal produces a spacing indicationin the printout signal, indicating spacing between words andpunctuation, said printout signal providing either (a) dot signals for atypographic unit, or (b) punctuation signals responsive to specificvoiced inputs, e.g., comma," semicolon."

15. The invention of claim 14 wherein the transcriber module (FIG. 9)comprises storage of phoneme sequences responsive to (a) an indicationof stress in the oral input signal, (b) output from the regrouper means,and (c) the out-

1. Speech-to-writer apparatus comprising: a detection and analysistransducer module receiving an oral and a throat signal input and havingsound separation means for detecting, differentiating, processing andproducing speech sound signals according to at least the followingstated categories: (1) vowels and semivowels, (2) nasals, (3) unvoicedfricatives, (4) voiced fricatives, (5) unvoiced stops, and (6) voicedstopS, said sound separation means (FIG. 2) having sensors responsive tothe oral signal and throat signal inputs, a stops-or-silence meansresponsive to said sensors, ratiometer circuits fed by said sensors andsaid stops-orsilence means to produce an output signal, and a pluralityof logic gate means selectively responsive to outputs from said sensors,said stops-or-silence means, said ratiometer circuits, for singularlypassing processed speech.
 2. The invention according to claim 1 whereinsaid sound signals produced by said transducer module are fed separatelyto a transcriber module having a syllable storage and a word-vocabularystorage.
 3. The invention according to claim 1 wherein a printout signalmeans for said transcriber module is connected to a typographic unitproducing a written output of either conventionally spelled words orsyllabic utterances.
 4. The invention according to claim 1 wherein saidsound separation means (FIG. 2) has: an oral sensor gate receiving aninput of said oral signal and producing digital outputs indicative oforal ON and oral OFF, a throat sensor gate and low-pass filter receivingan input of throat signal and producing digital outputs indicative ofthroat ON and throat OFF signal, differentiator means responsive to saidoral sensor, throat differentiator responsive to said throat sensor,said stops-or-silence unit receiving inputs of said oral signal, saidoral ON and said oral OFF signals, said throat ON and OFF signals, andsaid oral and throat differentiator outputs, said ratiometer circuitsreceiving inputs from said oral and throat sensor gates, said oral andthroat differentiator outputs and producing ratioed output signals, andeach said logic gate means receiving said oral signal, including anunvoiced stop gate receiving outputs from said stop-or-silence unit, avoiced stop gate receiving outputs from said unvoiced stop gate and saidstop-or-silence unit, an unvoiced fricative gate receiving said oral ONsignals and said throat OFF signal, a voiced fricative gate receivingsaid throat ON signal and one of said ratioed output signals, and avowel gate receiving outputs from said oral gate and one of said ratioedoutput signals.
 5. The invention according to claim 4 wherein (FIG. 4)said unvoiced stop gate provides an output to a stop unit comprised of aterminal for receiving signals indicative of an unvoiced stop that isundifferentiable as to whether it is /p/, /t/ or /k/, first, second andthird band-pass filters for passing 1,800-2, 200, 3,800-4,600 and3,400-3,800 cycles, respectively, and receiving the outputs of saidunvoiced stop gate and said stops-or-silence unit producing filteroutput signals, and a first, second and third comparator, said firstcomparator receiving output signals from said first and second filters,said second comparator receiving output signals from said second andthird filters, and said third comparator receiving output signals fromsaid first and third filters.
 6. The invention according to claim 1wherein (FIG. 3) said stops-or-silence means for voiced stops, unvoicedstops, and for silence, comprises a comparator 146 receiving outputsfrom said oral and throat differentiators and producing output when theamplitude of said throat differentiator output is equal to or greaterthan the amplitude of said oral differentiator output, a switch means126 receiving said produced output, said throat ON signal, and an outputfrom a second circuit indicating the presence of a stop, said secondcircuit having a timer 140 receiving inputs of said oral OFF and throatOFF signals and producing a delay gate output, a switch 141 receivinginputs of said oral differentiator and said delay gate output producingcomplementary outputs identified as silence signal without dt and stopwith dt, a timer gate (0.15 seconds max.) 134 rEceiving inputs of saidoral ON and OFF and oral differentiator signals, to pass a predetermineddelayed signal representing undifferentiated unvoiced stops, a silencetimer gate 130 receiving inputs of said silence signal without dt andsaid oral ON signal producing a silence signal, an unvoiced stop gate142 receiving inputs from said throat OFF signal and said stop with dtsignal, a timer (0.01) delay gate 132 receiving inputs of said oralsignal from said oral differentiator and from said second circuit meansproducing mutually exclusive outputs of greater or less than 0.01-seconddelay duration, a timer (0.06) 136 receiving inputs of said less than0.01-second delay duration and said oral signal, and also from the saidoral differentiator, producing an output direct to the unvoiced stopstransducers, a delay switch (0.03) 144 receiving inputs of said morethan 0.01-second delay duration, and said oral differentiator, andproducing outputs direct to both voiced and unvoiced stops transducers.7. The invention of claim 1 wherein said detection and analysistransducer module comprises a nasal unit (FIG. 6) responsive to oral andthroat inputs, a plurality of filter comparators, one of saidcomparators deriving an /1/ signal and one deriving an undifferentiatednasal sound as a result of said added throat input.
 8. The invention ofclaim 1 wherein said detection and analysis transducer module comprisesa vowel detection unit (FIG. 7) responsive to oral input to providedetection and differentiation of single vowels from each other by ratiocomparison of first and second formant peaks to total signal strengthderiving vowel signals therefrom.
 9. The invention of claim 8 whereinare means for deriving (FIG. 7A) second formant peak amplitude signalswithout reference to its frequency which is accomplished byheterodyning.
 10. The invention of claim 9 wherein said transducermodule operates substantially as well with oral input signals fromeither a male or female voice.
 11. The invention of claim 8 wherein saidvowel detection unit includes a transducer 340 receiving an oral inputsignal and a signal indicative of the presence of an identified vowel,said transducer producing an output signal indicative of anundifferentiated vowel.
 12. The invention of claim 11 wherein saidtransducer module comprises a diphthong transducer (FIG. 8) thatdistinguishes diphthong sound signals from single vowel sound signals(371-376) by a differentiated oral signal applied to a memory, and afirst formant quotient signal and from a signal from the ratiocomparison of first formant peaks to total signal strengths (claim 9),said memory acting upon a comparator to condition diphthong gates(461-466) to pass a diphthong signal, said memory also acting on aswitch (434) to shunt nondiphthong sound signals to a transcribermodule.
 13. The invention of claim 2 wherein said transcriber module(FIG. 9) comprises a phoneme sequence sensor and designator (490) forreceiving signals indicative of fricatives, stops, vowels, diphthongs,nasals, and a silence signal; a regrouper and storage means 494 ofpreselected phoneme groupings responsive to the output of thedesignator, a syllable retainer 510 having a storage capacity ofsyllables to be actuated by the regrouper means output, and a wordvocabulary 516 cumulatively responsive to the consecutive output of thesyllable retainer for producing print out signals of the longest wordforms provided by spoken input.
 14. The invention of claim 13 whereinsaid transcriber module in response to receiving said silence signalproduces a spacing indication in the printout signal, indicating spacingbetween words and punctuation, said printout signal providing either (a)dot signals for a typographic unit, or (b) punctuation signalsresponsive to specific voiced inputs, e.g., ''''comma,''''''''semicolon.''''
 15. The invention of claim 14 Wherein the transcribermodule (FIG. 9) comprises storage of phoneme sequences responsive to (a)an indication of stress in the oral input signal, (b) output from theregrouper means, and (c) the output of the syllable retainer, forproducing a printout signal for short words and symbols in capitalletters showing said stress.
 16. The invention of claim 15 wherein thetransducer module produces printout signals for driving a Brailleprinting device.